We could differentiate it as a quotient but it's a 
little easier to first turn it into a product:









A clever trick we often play here is to factor out the smallest exponent, the
 power.

When we factor the  power out of the  power what's left inside is 
the difference of the exponents 
It's just the first power!

We factor  out:









We write the negative exponent in the bottom as a positive exponent:



Edwin